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mm/hmm: add tests for hmm_pfn_to_map_order()

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Add a sanity test for hmm_range_fault() returning the page mapping size
order.

Link: https://lore.kernel.org/r/20200701225352.9649-6-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Ralph Campbell 2020-07-01 15:53:52 -07:00 committed by Jason Gunthorpe
parent 3b50a6e536
commit e478425bec
3 changed files with 84 additions and 0 deletions
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4
lib/test_hmm.c
View File

@ -766,6 +766,10 @@ static void dmirror_mkentry(struct dmirror *dmirror, struct hmm_range *range,
*perm |= HMM_DMIRROR_PROT_WRITE;
else
*perm |= HMM_DMIRROR_PROT_READ;
if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PMD_SHIFT)
*perm |= HMM_DMIRROR_PROT_PMD;
else if (hmm_pfn_to_map_order(entry) + PAGE_SHIFT == PUD_SHIFT)
*perm |= HMM_DMIRROR_PROT_PUD;
}
static bool dmirror_snapshot_invalidate(struct mmu_interval_notifier *mni,

4
lib/test_hmm_uapi.h
View File

@ -40,6 +40,8 @@ struct hmm_dmirror_cmd {
* HMM_DMIRROR_PROT_NONE: unpopulated PTE or PTE with no access
* HMM_DMIRROR_PROT_READ: read-only PTE
* HMM_DMIRROR_PROT_WRITE: read/write PTE
* HMM_DMIRROR_PROT_PMD: PMD sized page is fully mapped by same permissions
* HMM_DMIRROR_PROT_PUD: PUD sized page is fully mapped by same permissions
* HMM_DMIRROR_PROT_ZERO: special read-only zero page
* HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL: Migrated device private page on the
* device the ioctl() is made
@ -51,6 +53,8 @@ enum {
HMM_DMIRROR_PROT_NONE = 0x00,
HMM_DMIRROR_PROT_READ = 0x01,
HMM_DMIRROR_PROT_WRITE = 0x02,
HMM_DMIRROR_PROT_PMD = 0x04,
HMM_DMIRROR_PROT_PUD = 0x08,
HMM_DMIRROR_PROT_ZERO = 0x10,
HMM_DMIRROR_PROT_DEV_PRIVATE_LOCAL = 0x20,
HMM_DMIRROR_PROT_DEV_PRIVATE_REMOTE = 0x30,

76
tools/testing/selftests/vm/hmm-tests.c
View File

@ -1291,6 +1291,82 @@ TEST_F(hmm2, snapshot)
hmm_buffer_free(buffer);
}
/*
* Test the hmm_range_fault() HMM_PFN_PMD flag for large pages that
* should be mapped by a large page table entry.
*/
TEST_F(hmm, compound)
{
struct hmm_buffer *buffer;
unsigned long npages;
unsigned long size;
int *ptr;
unsigned char *m;
int ret;
long pagesizes[4];
int n, idx;
unsigned long i;
/* Skip test if we can't allocate a hugetlbfs page. */
n = gethugepagesizes(pagesizes, 4);
if (n <= 0)
return;
for (idx = 0; --n > 0; ) {
if (pagesizes[n] < pagesizes[idx])
idx = n;
}
size = ALIGN(TWOMEG, pagesizes[idx]);
npages = size >> self->page_shift;
buffer = malloc(sizeof(*buffer));
ASSERT_NE(buffer, NULL);
buffer->ptr = get_hugepage_region(size, GHR_STRICT);
if (buffer->ptr == NULL) {
free(buffer);
return;
}
buffer->size = size;
buffer->mirror = malloc(npages);
ASSERT_NE(buffer->mirror, NULL);
/* Initialize the pages the device will snapshot in buffer->ptr. */
for (i = 0, ptr = buffer->ptr; i < size / sizeof(*ptr); ++i)
ptr[i] = i;
/* Simulate a device snapshotting CPU pagetables. */
ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, npages);
/* Check what the device saw. */
m = buffer->mirror;
for (i = 0; i < npages; ++i)
ASSERT_EQ(m[i], HMM_DMIRROR_PROT_WRITE |
HMM_DMIRROR_PROT_PMD);
/* Make the region read-only. */
ret = mprotect(buffer->ptr, size, PROT_READ);
ASSERT_EQ(ret, 0);
/* Simulate a device snapshotting CPU pagetables. */
ret = hmm_dmirror_cmd(self->fd, HMM_DMIRROR_SNAPSHOT, buffer, npages);
ASSERT_EQ(ret, 0);
ASSERT_EQ(buffer->cpages, npages);
/* Check what the device saw. */
m = buffer->mirror;
for (i = 0; i < npages; ++i)
ASSERT_EQ(m[i], HMM_DMIRROR_PROT_READ |
HMM_DMIRROR_PROT_PMD);
free_hugepage_region(buffer->ptr);
buffer->ptr = NULL;
hmm_buffer_free(buffer);
}
/*
* Test two devices reading the same memory (double mapped).
*/